Questão 3332576

3332576 Ano: 2024
Disciplina: TI - Banco de Dados
Banca: UFMT
Orgão: UFMT

Provas:

Analista de TI
Provas ×

SGBDsPostgreSQL

São dadas a seguir duas tabelas no banco de dados PostgreSQL: orders e customers.
CREATE TABLE customers ( customer_id SERIAL PRIMARY KEY, customer_name VARCHAR(100) );

CREATE TABLE orders ( order_id SERIAL PRIMARY KEY, order_date DATE, customer_id INT, FOREIGN KEY (customer_id) REFERENCES customers(customer_id) );

Qual alternativa altera a definição dessa chave estrangeira de modo que, quando um registro na tabela customers for deletado, a coluna customer_id na tabela orders seja atualizada para NULL?

ALTER TABLE orders

DROP CONSTRAINT orders_customer_id_fkey,

ADD CONSTRAINT orders_customer_id_fkey FOREIGN KEY (customer_id)

REFERENCES customers(customer_id) ON DELETE RESTRICT NULL;

ALTER TABLE orders

DROP CONSTRAINT orders_customer_id_fkey,

ADD CONSTRAINT orders_customer_id_fkey FOREIGN KEY (customer_id)

REFERENCES customers(customer_id) ON DELETE CASCADE NULL;

ALTER TABLE orders

DROP CONSTRAINT orders_customer_id_fkey,

ADD CONSTRAINT orders_customer_id_fkey FOREIGN KEY (customer_id)

REFERENCES customers(customer_id) ON DELETE SET DEFAULT NULL;